Multiple gauging device

ABSTRACT

For use in laying out duct or box-like structures, a gauging device having multiple sides, including appendages in predetermined positions, with rotatable connection means for attaching the gauge to a measuring tape (or it can be integral with a measuring bar), with the appendages serving to position the tape or the bar so as to add various predetermined lengths to the tape or bar equivalent to material lapped or cut away in the fabrication of corner and lap joints or seams with the measuring tape or bar indicating directly in terms of the specified or finished inside dimensions of the structure. The appendages are configurated to enable measuring from points on each of several variously oriented planes.

This is a division of application Ser. No. 053,951, filed July 10, 1970,now U.S. Pat. No. 3,824,695.

The present invention relates to gauging devices essentially a short,multi-sided bar carrying appendages, locating marks, and certaindiagrammatical data along its sides which may be used in rotatable(around its longitudinal axis) attachment with a measuring tape, orrigidly attached to a measuring bar.

The gauging device has the capacity to add several dimensions to thelength of the tape, or bar, when measuring horizontally or linearlyfrom, e.g. a mark or point on a horizontal surface, from a dependentvertical face, or from the intersection of two given declining slopedfaces, or from the intersection of a declining sloped face and ahorizontal face.

The several dimensions are those allowances made in the layout andsubsequent cutting of flat stock, of appreciable thickness, for thefabrication of air ducts, conduits of rectangular cross-section, boxes,or box-like structures when the sides of the structures are joined bymeans of rabbet, butt, mitre, and ship-lap type joints, the devicesadding certain predetermined lengths to the measuring tape, or bar, tocompensate for the material lapped or cut away and also for thecutter-to-guide-edge width of the cutting tool, in order that themeasuring tape, or bar, may directly indicate the guide-edge positionfor each subsequent cut in terms of the finished, or specified, insidedimensions of the structure.

The invention finds wide-spread use in the layout and cutting of fiberglass duet board manufactured for the fabrication of ducts for airconditioning systems. The material is an insulating board, faced on oneside with a thin aluminum sheet which serves as a structural band tohold the sides of the duct together, and also as a vapor barrier. Theboard is manufactured in three thicknesses, 1, 11/2, and 2 inches. Thethicker materials, of course, require greater seam allowances, and threedifferent size layout devices are required when working with the threethicknesses, each similar except in length, size and longitudinalplacement of the appendages, longitudinal placement of the locatingmarks, and the numerical data on the sides thereof, but the operatingprinciple being the same.

In a typical example the corner joints of a section of duct are cutacross the board, parallel to the short side (normally 4 feet), and ifthe length (normally ten feet) of the board is sufficient, the jointsfor the four corners are cut. The two end cuts are then fastenedtogether to form the finished section, the duct having been made, inthis instance from one continuous piece, in the following manner:

The board is placed on a work table with the aluminum facing next to thetable. The first cut is made by a knife, vertically through the board,including the aluminum facing (note this cut is not necessary if theedge is in "as manufactured" condition). The next three cuts are groovesformed by the intersection of two 45° mitre faces forming at the bottomof the groove an included angle of 90° with its vertex located slightlyabove the aluminum facing. These grooves are cut by a special tool. Thenext to last cut is made by a knife, vertically through the fiber glassbut not through the aluminum facing. A short distance from the lattercut, a second knife cut is made through both the fiber glass and thealuminum facing. The fiber glass between these two latter cuts is thencut away from the aluminum facing leaving a flap or tab (this latterfiber glass edge will hereinafter be referred to as a butt edge). Next,a special tool is used to cut a rabbet out of the top face of the boardand along the edge of the first knife cut (an edge so formed willhereinafter be referred to as a rabbeted edge, whether actuallyrabbeted, or only a vertical knife cut to be rabbeted later) this toform a pocket to receive the above butt edge with its adjoining tab tobe used to overlap the outside corner.

At this point, all that is necessary to form the duct is to bring thefirst side up to a vertical position, the same for the third side, thefourth side is swung up and over to mate its butt edge into the rabbetededge of the first side, bend the tab over the corner thus formed, stapleit down (to the outside face of the first side) and seal the edge of thetab with a special tape.

However, before the board is folded to form a duct, the above mentionedrabbeting tool is moved along one of the edges normal to the corner seamcuts, cutting a rabbet out of the top surface of the board; a secondrabbeting tool is moved along the opposite edge of the board to cut arabbet in the bottom surface of the board, just above, and adjacent tothe aluminum facing. These latter cuts form the male and female edges ofship-lap joints used to join one section of duct to another.

In order to fabricate ducts of large cross-sectional area, and also, inorder to reduce waste, it becomes necessary, rather than making the ductfrom one continuous piece of board, as described above, to make the ductfrom four separate pieces, or of two L-sections, or by means of aU-section and a cap piece. Air conditioning duct sizes are always given,or specified, in terms of the inside width and depth dimensions (theterm "dimension" not otherwise qualified, shall be, herein, construed tomean only the width of a side, top, or bottom panel of a section ofduct, or of a duct fitting). With this in mind, and in view of the factthat all but one of the above joint cuts affect the inside dimensions,and also mindful that continuous corner joints are formed by twointersecting mitre cuts, and that non-continuous corner joints are madeup of a rabbeted edge, a mating butt edge, and a stapling tab, and againmindful that, thus far in the interest of simplicity of description,nothing has been mentioned regarding the layout of elbow and toefittings; it becomes quite apparent that the dimensional allowances thatmust be made, to compensate for the material lapped, or cut away, etc.,are many and varied.

In addition to the above, it must also be determined whether theremaining board, or potential scrap, is large enough for the fabricationof ducts, to desired sizes, by means of joining two L-sections, or byjoining a U-section with a cap piece, or by joining four separatepieces, or ideally, in one piece, as outlined above, the required lengthof board being, of course, the total of the pertinent side dimensionsplus the total of the pertinent seam allowances.

Currently, there are two methods of coping with the above, as set forthby the manufacturers of duct board; briefly as follows; the first iscalled the "guide edge method", in which the seam allowances pertainingto the first side are added to the given side dimension, and from thisis substracted the center-to-guide-edge width of the grooving tool, togive a subtotal; to this sub-total is added the seam allowances and thegiven dimension of the next side, to give the next sub-total, etc.,continuing for the rest of the sides. Then, beginning at the lower lefthand corner of the board for each measurement, each of the abovesub-totaled dimensions is marked along the lower edge and the samedimensioning is repeated, beginning at the upper left hand corner. Thesehand constructed marks locate the position of the straight edge againstwhich the cutting tool is guided. The reason for beginning at the lefthand of the board, and for the one substraction, is that this places theguide edge on the left hand side of the subsequent cut, allowing thecutting to be done with the right hand and also it assures that theguide edge will be on the board in the event that the board is no longerthan that necessary from which to cut the section. These many necessarycalculations require addition and subtraction of fractions withattendant errors and heavy loss or scrap of duct board.

According to one of the board manufacture's fabrication manuals,contractors using the board evidently thought this method unnecessarilycomplicated, and developed the "center-line" method, which is the sameas the foregoing except that the guide edge is omitted. This does awaywith the above subtraction and also allows the dimensioning to begin atthe left, or the right hand edge. The dimensions are marked along boththe upper and lower edges of the board, as in the foregoing. Then, usinga straight edge, lines are drawn, across the board, between thecorresponding dimension marks; these are the center-lines of thesubsequent cuts. The center of the grooving tool is marked on top of theleading edge, and the cuts are then made free-hand, lining up the markon the tool with the line on the board. (There are two problems here:one is that, due to the abrasive nature of the material, the workmanspends an appreciable amount of time sharpening pencils; the other isthat the mark on the grooving tool being about an inch above the line onthe board, if the workman's line of vision is not exactly normal to theboard the cut is not accurately made, and this, when the board is foldedto become a section of duct, causes the corners of the duct to be "outof square", which, of course, causes difficulty when joining one sectionof duct to another, and particularly when the adjacent section is out ofsquare in the opposite direction.)

The manufacturers make available to the contractors, pads ofwork-sheets, in three different forms, showing cross-sections of theboard with various combinations of corner joint cuts, etc., the mainportion of the sheet containing ruled in areas in which are to beinserted the given duct dimensions, and between these areas the seamallowances are printed, apparently in an attempt to reduce theprobability of error. The manufacturer also recommends that once thesework-sheets are filled in, for given duct sizes, they be filed forfuture references.

The invention herein described, reduces all of the above to a verysimple, straight-forward, and accurate procedure, even for theinexperienced.

The gauge is attached to a measuring tape in one embodiment, asmentioned earlier. The tape is merely a spring return type with capacityto measure 6 to 8 feet. The housing of the tape is mounted in such a waythat it may be removably, or rotatably (around a vertical axis) carriedon the blade (straight-edge portion) of a T-square. The alternativestructure to the rotatable one comprises a roll-up tape on a clip, orplate with depending flange, which is carried by the T-square and whichpractically falls out of the way after each use.

In using the present invention, the board is placed on the cutting tablewith its aluminum facing against the table. The blade of the T-square isplaced across the duct board (in the direction in which the corner seamsare to be cut), and with its head bearing against the long side of thetable adjacent to the worker. It is now only necessary to properlyposition the gauge at the right hand edge, or at the immediatelypreceding cut to the right of the T-square, as the case may be, move theT-square to the left until the right hand edge of the blade coincideswith the measurement (i.e. the desired known inside dimension of thatside of the duct) as indicated on the tape, and the blade is in thecorrect position to provide the guide edge for the subsequent cut.

On each side of the gauge are shown certain diagrammatical data whichgenerally depicts the sides of duct in stretchout cross-section. Theportions of these sections containing diagonal lines, circular markswith lines extending therethrough to appendages, or to locating marks,represent the sides having those particular combinations of cornerjoints for which the correct lengths are added, to that shown by thetape, by positioning the indicated appendage, or locating mark, at theimmediately preceding groove cut, or knife cut, or butt edge, as thecase may be. This will be explained in greater detail in reference tothe drawings.

Also, in the diagrammatical data, in addition to the abovecross-sections containing the diagonal lines, which are used as aboveindicated, there are cross-sections which are shown in outline only.Those are included only for information as to the length of board, inaddition to the dimension, or sum of the dimensions, respectively, ofthe side, or combination of sides, required to cut said side, orcombination of sides including the related combinations of corner seams.This will also be further explained in connection with the descriptionof the drawings.

With the foregoing in mind, it is among the objects of this invention toprovide apparatus for gauging purposes wherein, in connection with alinear measuring arrangement, the present invention directly adds any ofseveral predetermined dimensions to the scale of the linear measurerwhen measuring from points on each of several variously oriented planes.

Another object of the present invention is the provision of a measuringgauge, per se, which has a body and appendages related thereto inpredetermined fashion.

It is another object of the invention to incorporate such a gauge with amarked bar or linear extendable measuring device.

Yet another object of the invention is the provision of apparatusincorporating the use of the invention in conjunction with a T-square orstraight edge for laying out duct and duct fittings to desired insidedimensions.

Finally, a still further object, is the provision of a gauging deviceusing the described principle which device is simple, straight forward,accurate, and readily useable by the inexperienced.

The invention will be better understood from a reading of the followingdetailed description thereof, when taken in the light of theaccompanying drawings wherein:

FIG. 1 is a view in perspective showing a typical stretchout of a boardto be fabricated into duct,

FIG. 2 is a view in end elevation of the duct fabricated from the boardof FIG. 1,

FIG. 3 shows in perspective a gauge of the present invention inconnection with a reelable linear measuring device,

FIG. 4 is a view in perspective of a modification of the gauge of FIG.3, depicted in association with a linear bar measuring device,

FIG. 5 is a view in side elevation with dotted interior construction ofthe gauge of the first embodiment,

FIG. 6 is an end view of the structure of FIG. 5,

FIG. 7 is a view in side elevation of the gauge of FIG. 5 showing afirst side thereof,

FIG. 8 shows the second side of the same gauge,

FIG. 8a is a view similar to FIG. 8 except that the indioia associatedwith the operative appendages has been modified,

FIG. 9 shows a third side of the gauge of FIG. 5,

FIG. 10 shows a fourth side of the gauge of FIG. 5,

FIG. 10a shows the fourth side of the gauge of FIG. 5, but withdifferent indioia for use with the operative appendages thereof,

FIG. 11 is a view partly in section and partly in side elevation showingthe gauge of FIGS. 3 and 5 in operative relation to a duct board, for afirst mitre or groove cut,

FIG. 12 shows the structure of FIG. 11 positioned in the former groovecut and measuring for a second groove cut,

FIG. 13 shows the above structure advanced along the board for the nextcut,

FIG. 14 shows an alternate structure for mounting the reelable measuringtape for use in the subject invention.

FIG. 15 is a view in side elevation of the first side of the gauge ofthe second embodiment as shown in perspective in FIG. 4,

FIG. 16 shows the second side of this embodiment,

FIG. 17 shows the third side of this embodiment,

FIG. 18 shows the fourth side of this embodiment,

FIG. 19 is a view in side elevation of the gauge of this embodiment inrelation to the linear measuring bar,

FIG. 20 is an end view of the structure of FIG. 19,

FIG. 21 is a side view of a third embodiment of the gauge of the presentinvention showing the internal construction in dotted outline,

FIG. 22 is an end view of the structure of FIG. 21,

FIG. 23 is a top view of the structure of FIG. 21,

FIG. 24 is a view in side elevation of a further embodiment of the gaugeof the present invention,

FIG. 25 is an end view of the structure of FIG. 24 without theconnection means,

FIGS. 26 and 27 show the gauge adjustably attached to a linear measuringdevice.

Referring now to FIG. 1, there is illustrated a typical material 25 fromwhich it is desired to fabricate, for example, the structure 27, shownin FIG. 2. For purposes of the present description, it will be assumedthat the material 25 is a fiber glass duct board and it is desired touse this board to fabricate the duct 27 of FIG. 2, knowing the insidedimensions of the duct. It is, of course, necessary to cut the severalgrooves in the correct positions in order that the board 25 can befolded and secured in the configuration of the duct 27 while maintaininga high degree of accuracy to the predetermined dimensions. Measurementsprogress from the right hand face 29 of board 25 toward the left,forming cuts and grooves in sequence. The first cut will square or truethe edge 25, unless it is already in such condition as received from themanufacturer.

The next out, or the first groove out, is that necessary to form groove31 which enables bending of the board to define corner 30 of duct 27.Thus, a distance is laid out from edge 29 to either edge or to thecenter of groove 31 being formed, which positions guide edge 33 of theT-square 35 so that the cutter of the grooving tool 38, guided againstthe edge of the T-square, will form the groove in proper relation to thebeginning edge 29 so that the side 37 so cut will be of the correctdimension when the duct is assembled. Then, in succession, out 41 ismade to form corner 43 in similar fashion, cut 45 is made similarly toform corner 47, next, a knife cut is made vertically through the fiberglass to, but not through, the aluminum foil, to form a butt edge (x),and finally a last cut is made to provide for a tab 51 (see FIG. 2)which will overlap side 37 when the duct is formed, the beginning edgeof side 37 being rabbeted to receive the butt edge (x).

In FIG. 3, a first embodiment of gauge 61 is shown with rotatableconnection means 63 linking the same to a tape 65 reelable into and outof housing 67. Housing 67 is turn fixed to a base 69 comprising ahorizontal reach 71 and a vertical reach on depending flange 73.

In general, it will be noted that the gauge 61 includes a body 75 andappendages 77, 79, and 81 extending outwardly therefrom at predeterminedlocations. The use of this device will further be explained inconnection with the detailed showings of figures later to be described.

In FIG. 4, there is shown in perspective, a second embodiment of theinvention which comprises a modified gauge 91 having a body 93 anddifferently located appendages 95, 97, and 99. This gauge is connectedto a linear measuring device comprising bar 101 by any suitable means,as for example, the plastic tenon plug 103 extending between the hollowinteriors of body 91 and bar 101.

It should be noted at this point that gauges 81 and 91 areinterchangeable relative to linear measuring devices, and either may beused with my type of linear measuring device available, including even,eg. yard sticks or strings.

FIGS. 7-10 show the respective sides of the gauge 61 of FIGS. 5 and 6with attachments for receiving a linear measurer.

In FIG. 7, a first side view, there is shown the appendage 77 in thelower or working position on the body 75 of the gauge 61 and immediatelyabove appendage 77, but on body 75, are shown two diagonally lined,cross-sectional diagrams 121 and 122, of sides of a duct, each having adifferent combination of corner joints. In cutting the side of 121, thevertical face of appendage 77 is hooked over the right hand edge 29 ofthe board 25 (see FIG. 11), corresponding to the right hand edge of theside depicted in diagram 121, which, at this point, has not beenrabbeted, and the tape 65 to which the gauge 61 is attached, is pulledto the left. The blade 34 of a T-square 35, placed beneath the tape 65will have its guide edge 33 located at the correct position for themitre cut 31 at the left of side 37 when its guide-edge 33 coincideswith the desired inside dimension of the duct, as read directly from thetape at the number corresponding to the inside dimension. Theconfiguration of diagram 122 is cut in like manner, except that thesloped face of appendage 77 is held against the far sloped face 78 (seealso FIG. 12) of the immediately preceding mitre or groove cut 31, whichpositions the vertical face of the appendage directly above, and inregister with, the intersection of the two mitre faces, makingunnecessary any need for visual inspection.

FIG. 8, a second side view, shows appendage 81 in the working position.On the body of the gauge, and immediately above appendage 81 are twodiagonally lined cross-sectional diagrams, 131 and 133, each depicting adifferent combination of corner joints. In cutting the side of diagram131, the sloped face of the appendage 81 is held against the far side ofthe groove cut to the right of the side, and the guide-edge positionedas explained previously. In this case, the cut is made with a knife,vertically through the board; the rabbet 136 shown in the cross-sectionof 131 is made later, with a special rabbeting tool which is guided bythe top surface and against the vertical edge of the board 25, made bythe cut just mentioned.

Attached to and extending to the right of the section 131 is a side 139shown in outline only, and extending to the right of section 139 is astapling tab 141. These two sections 131, 139 and the stapling tab 141comprise an L section, two such complementing L sections being joined toform a complete duct section.

Above this combination of sides is shown a dimension line 145 and thenumerical data "D±4-5" which intersects that the total length of theboard required to cut these two sides, plus the allowances for thecorner joints, plus the stapling tab 141 is the sum of the sidedimensions "D" plus four and five eighths inches. (All dimensions soshown in the drawings are in inches and eighths.)

The side 133 shown just below 131 is cut in like manner except that thevertical face of the appendage 81 is hooked over the right hand edge ofthe board. As this cross-section is used as two opposite sides of a fourpiece duct section, above it is shown the length of board required, i.e.D+1-6.

In FIG. 9, a third side view, shows cross-sections of two sides 150 and151, containing corner joints, all of which with the exception of one152, are butt edges with adjoining stapling tabs. Cutting the fiberglass material from stapling tabs is more quickly and conveniently doneas a last operation; therefore, locating or register marks are shownadjacent to a plane lower surface 155, the selected locating mark beingplaced directly over the mark made by the knife during the prior cut,when measuring therefrom to position the guide-edge for the subsequentcut. For example, in cutting the side 150 with its adjoining staplingtabs, the locating mark 156 is placed so that it is directly over theright hand edge of the board, the measuring tape drawn to the left, and,as the stapling tap is not a part of the inside dimension of the duct,the guide-edge is placed at the 0 end of the tape, and the first buttedge cut 100 is made. The locating mark 161 is placed over the latterknife cut 100, the guide-edge andd tape moved to the left until theguide-edge coincides with the inside dimension of the side, as indicatedon the tape, and the second butt edge cut 164 is made. The secondstapling tab 165 is cut in a manner similar to the first, the locatingmark 156 being placed over the knife mark made during the latter buttedge cut 164, etc. Two of the 150 cross-sections are used as oppositesides of a four pice duct section (with two of the 133 (FIGS. 8)cross-sections mentioned above), and so the length of the materialrequired to cut the section together with its stapling tabs, is shownabove it.

The cross-section 151 is cut similarly to the above, the locating mark170 is positioned over the knife mark made by the butt edge cut, etc.

FIG. 10, a fourth side view, shows appendage 79 in the lower or workingposition. On the body 75 of the gauge 61 and immediately above theappendage 79 is shown a diagonally lined cross-section of a side of aduct 175. The guide-edge is positioned and the side is cut, similarly tothe above described (see FIG. 13).

Extending to the right from the section 175 are three sidecross-sections, shown in outline only, which together with the section175 comprise those sides, and corner joints required to fabricate asection of duct from one continuous piece of material, and so, abovethis series of sections is shown the length of material required(D+8-0). Above said series, is a second series of sections, shown inoutline only, which make up those sides and corner joints required tofabricate a U section, and so, above this series is shown the length ofmaterial required (D+5-2). (Note a U section plus a cap piece 150 makeup a duct section.)

It will be noticed that the gauge provides for positioning theguide-edge from each of the joint types to each of the others, whichallows the worker to reverse the cutting sequence, if so desired.

The gauge, as above described, without modification, is applicable inthe lay-out of duct fittings, such as tees, elbows, and transitions (atransition is a more or less straight through fitting which changesduring the course of its length, from a rectangular section of givendimensions to that of different dimensions, or to a like, or unlike,section located on a different longitudinal center-line) when these arefabricated by means of joining four separate pieces, in a manner similarto that in which sheet-metal craftsmen make similar fittings from steelsheets. However, one of the manufacturers of fiber glass duct board hasdeveloped a method for fabricating tees and elbows which is much moredirect and less time consuming, and incidentally, one for which theboard is ideally suited, in that an elbow is made up of only two pieces,and a tee, in never more than two pieces, and under certaincircumstances, it may be made in only one piece. Thus FIGS. 8a and 10aare shown as alternates to FIGS. 8 and 10 with the former diagrammaticaland informational data modified to include the above indicated methodsfor fabricating tees and elbows, following the principles hereindescribed.

FIG. 11 shows the gauge in operation, as used in positioning the guideedge for a first mitre, or groove cut, in a sequence of corner jointcuts as made in fabricating a duct section from one continuous piece ofduct board, as will be further shown in the following figures. Thehousing 201 of a spring-return type measuring tape 65 is fixedly mountedon a circular block 203, or disc, which in turn, is loosely carriedwithin a channel type blade 34 of T-square 35 so that the housing isfree to be rotated around a vertical axis. The gauge is shown with itsappendage 77 hooked over the right hand edge 20 of the fiber glass board25 placed so that the aluminum foil 205 to which the fiber glass isbonded, is on the lower side. The guide edge 33 is moved to the leftuntil the desired inside dimension of that side of the duct, asindicated by the tape (e.g. 10 inches) coincides with the guide-edge.The gauge 81 is lifted and brought toward the guide-edge 33, allowingthe tape 65 to be retrieved into the housing 201, then moved, rotatingthe housing, so as to clear the guide-edge. Mitre cutting tool orgrooving tool 37 is moved across the board 25, and in contact with theguide-edge. The groove cut, so executed, will measure 10 inches from theintersection of the right hand face of the groove cut with the surfaceof the board, to the vertical dotted line 210 near the right hand edgeof the board. (The above dotted line, together with the adjoininghorizontal dotted line, enclose that portion of the board later removedby a rabbeting tool.)

The gauge 61 is rotatably connected to tape 65 through chain 211 set inangle 212 in turn riveted to tape 65. The opposite end of chain 211 isconnected to a yoke 214 in turn anchored by bolt 215 through jam nuts216 and 217. This construction permits ready use of all sides of gauge61 and allows longitudinal adjustment of gauge 61, and particularly itsmeasuring appendages and indicia relative to the zero on tape throughmovement of nuts 216 and 217. This adjustment permits cutting of theduct slightly larger or smaller, e.g. for fitting it to metal duct.

The tape zero is offset from the body 75 to provide maximum movement ofthe gauge relative to the tape to avoid damage.

It is interesting to note that while the gauge has a plurality ofpredetermined measurements and configurations or defining arms orappendages, nevertheless the duct may be cut and formed to any sizedesired including a zero opening.

FIG. 12 shows the gauge with its appendage 77 positioned in the formergroove cut 31, and the guide-edge moved to the left into position for asecond groove cut 41, which in this case, is for a side with an insidedimension of 7 inches.

A third groove cut 45 is made similarly to the above, except spaced foran inside dimension of 10 inches, and the side so cut will be locatedopposite the side 37 already cut.

FIG. 13 shows appendage 79 positioned in the third groove cut 45, theguide-edge 33 moved to the left to coincide with the 7 inches mark onthe tape. At this position of the guide-edge, a knife cut is made(dotted line 211) through the fiber glass, and to, but not through thealuminum vapor barrier, to form a butt edge which is to fit into therabbet, which is to be cut in the beginning edge shown in FIG. 11 asmentioned above.

In FIG. 14, is shown the alternative method of mounting the tape housing67 (see FIG. 3) wherein the housing is fixedly mounted on a flangedplate 69, in a manner allowing the assembly to be carried on the blade34 of T-square 35 by hooking the flange 73 over the left edge of theblade 34. This is advantageous, under some circumstances, as comparedwith the disc mounting, in the lay-out and cutting of duct fittings dueto the craftsman being concerned with the length of the sides, as wellas the width, the plate and flange mounting, of course, being instantlyremovable from the blade, proves more convenient in laying out thelength measurement. Also the edge of the mounting plate, opposite theflange, being wider than the tape, serves as a guide for the pencilmark.

While the embodiment of the invention just described is one embodiment,the gauge 91 of FIG. 4, which is pictured in greater detail in FIGS. 15through 20, will now be described because it more conveniently handlesthe situation where the sealing or stapling tab is provided at the righthand side of the board, which is the rabbeted face or edge. To achievethis, one appendage has been changed from one face of the gauge toanother face and the diagrammatical representations rearrangedaccordingly.

While the gauge body 93 is shown connected to measuring bar 101, it willbe appreciated that the gauge 91 may be employed with the reel 67 andtape 65 through use of the connection 63 of FIG. 3.

The right hand end of the board, which is to include the sealing tab, ispictured in the diagram 350 applied to the first side of the body 93,shown in FIG. 15. The right hand edge of the board corresponds to thevertical line 251 and the sealing tab is shown at 252. Thus, it isnecessary to make a cut to form edge 253 as the first step in forming aduct with the tab on the right.

The cut is made at face 253 by using the data on the second side of body93, as shown in FIG. 18. The right hand edge 251 of the board(corresponding to line 251 of FIG. 15) is aligned with arrow 254 on theplane surface 255 of gauge 91. Then the tape or bar zero (not shown inFIGS. 15 or 16), which is offset approximately one-half inch to the leftof the forward end 257 of body 93, marks the position on the board forthe first knife cut corresponding to the vertical surface 253 of FIG.15.

Next, since the material is not removed from the tab until later, thegauge 91 is merely slid forward until surface 261 of appendage 95 isdirectly over the first cut, i.e. vertical wall 253. Then the tape isdrawn out to the first measurement, e.g. 10 inches, and the first groove262 (see FIG. 15) is formed. It may be appreciated that both the cut andfirst groove were located by the plane surface 255 of body 93 withoutrotating the gauge 91.

In the manner heretofore explained, appendage 95 (FIG. 15), uponrotation of the gauge provides the anchor for laying out from groove togroove; and then again from the new groove to the last groove, therebyinherently incorporating dimensional accuracy in the stretchout.

For the left hand vertical wall or butt out, shown at 270, in diagram271 pictured on the fourth side of the body 93 in FIG. 18, appendage 97is used to measure from the third groove and locate the out line 270.

It may be appreciated that the third side, shown in FIG. 17 positionsthe measuring means for cutting from a groove to a rabbeted edge, anecessary function in cutting tee and elbow wrapper pieces, and alsocompletes the sequence of cut combinations in the reverse of the orderso far described, allowing the worker to lay-out, and cut, in eithersequence.

In FIGS. 19 and 20, the gauge 91 is shown attached to a square hollowalignment bar 101, marked in inches from 0 to 36 or 45 inches, forexample. The plastic plug 103 is pictured as holding the two componentstogether and the various appendages are identified by the same numbersheretofore employed. It will be appreciated that this bar is marked ininches on all four sides in order that it also may be rotated to bringinto play the plane surface 255 (FIG. 16) of the gauge, free ofprotruding appendages.

In FIGS. 21 through 23, there is shown a further mofified version whichemploys only fins or the like protruding therefrom to replace theforward vertical surfaces of the appendages. The same body constructionis used with the body 301 being comprised of a substantially hollowinjection molded plastic or even assembled wooden square configurationhaving therein the connection 303 carried by bolt 305, adjustable bynuts 306 and 307 to operate as heretofore. However, the forwardappendage is now depicted by fin 309 with the next appendage at 310 andthe rear appendage at 311. The disadvantage of using this configurationis, of course, that there is no rear slope on any of the appendages tofit the rear sloping wall of a groove and thus the fin must bemaintained vertically in the center of the groove. This requires visualinspection, whereas the prior described embodiments do not, but rathermay be held in place by feel.

Finally, FIGS. 24 and 25 show a further simplified version of a gauge350. Gauge 350 is fabricated of bent strip aluminum or steel with thebody portion 351 forming the forward end 352 for serving as a connectorfor chain 353, and the rear end 354 serving as a rest or stop forsitting on top of the board when either of the appendages 355 and 356 isbeing used. The disadvantage of this embodiment is that there is nosurface to carry indicia to guide the mechanic, nor will it lay out fromvertical face to vertical face. Of course, however, it is quiteinexpensive and otherwise useful.

In FIGS. 26 and 27, the gauge 91' is shown adjustably connected to thebar 101' through the use of bolt 401, which is threaded at 403 to engagethreads in the tenon 103' or in a metal threaded insert in the tenon103'. A plurality of shims 405 is provided to fix the adjusted distancebetween the rear wall 407 of gauge 91' and the front wall 409 for tenon103'. Thus the effective lay-out long available from this measuringarrangement is adjustable.

In FIG. 27 it may be seen that a groove and key-way 411 is provided toprevent the bar 101' from being rotated relative to the gauge 91'.

What is claimed is:
 1. A method for making ducts by positioning aguide-edge across an insulating structural board, having a metal foilvapor barrier on one side thereof, in a series of spaced apart positionsalong which selected tools may be guided to vertically cut, or to removematerial to form a groove in order that sides between lapped cornerjoints may be formed for the fabrication of ducts or like structures ofmultiple sides, in which said positioning is effected by a reelablelinear measurer with its housing demountably carried by said guide-edgeand having its zero end connected to a distance gauge comprisingdiagramatically indexed alignment means spaced therealong, being used ina series of similar dimensioning sequences beginning with an immediatelyprior edge, or cut, and subsequently indicating the position of theguide-edge for the next cut, directly in terms of the required insidedimension of that side of the structure after fabrication, comprisingthe steps of:placing the insulating board on a cutting table, or othersupport, with its metal foil side down, determining the specified insidedimensions of the required duct; selecting the one of the plurality ofalignment means which offsets the zero end of the linear measurers fromthe right hand edge of the board a predetermined distance equal to thewidth of a stapling flap; setting the position of the guide-edge at thezero end of the so-located linear measurer and parallel to the righthand edge of the board, making a vertical cut along the guide-edge,through the insulating material but not cutting the metal foil;separating the material, to the right of the cut, from the metal foil toform a stapling flap; mounting the linear measurer on the staight-edgeand placing a second alignment means in alignment with the edge thusexposed, said second alignment means offsetting the zero end of thelinear measurer a distance equal to the sum of the widths of material tobe removed from the first side of the structure being fabricated plusone half of the width of the grooving tool; moving the guide-edge to theleft, and parallel to the prior cut, until the specified insidedimension, of the side of the structure being layed off, as indicated bythe unreeling linear measurer, intersects the guide-edge, and with theguide-edge held in this position, placing the gauge and linear measurerto the left of the guide-edge, and moving the grooving tool along saidedge to cut a first groove; replacing the linear measurer with itshousing atop the guide-edge and placing said second alignment means inalignment with said last-mentioned groove; again moving the guide-edgeto the left, and parallel to the prior cut, to the point where therequired inside dimension of this side of, as indicated by the unreelinglinear measurer, intersects the guide-edge, placing the gauge andmeasurer to the left of the guide-edge, holding said edge in thisposition and moving the grooving tool therealong to cut a second groove;again mounting the linear measurer, together with its housing, atop theguide-edge, placing said second alignment means in alignment with thesecond groove, while holding the alignment means in this position,moving the guide-edge to the left, and parallel to the prior cut, untilsaid linear measurer, unreeling from its housing, indicates at itsintersection with the guide-edge, the required inside dimension of theside of the structure being layed-off, holding the guide-edge in thisposition and moving the grooving tool therealong to cut a third groove;and finally, again mounting the linear measurer, in its housing, atopthe guide-edge, placing a third alignment means in alignment with saidthird groove, and while holding the alignment means in this position,moving the guide-edge to the left and parallel to the prior cut untilsaid linear measurer, unreeling from its housing, indicates, at itsintersection with the guide-edge, the required inside dimension of thefourth and final side of the structure, holding the guide-edge in thislast mentioned position, making a cut therealong, moving a rabbetingtool along the edge formed by the first cut of the sequence, to form arabbet to receive said butt edge when the material is structured into aclosed configuration,
 2. A method of making ducts using measurements forsetting the positions of a guide-edge at spaced apart locations to guidecutting tools including a knife to make vertical cuts and those whichcut along more than one plane to form grooves in an insulating boardmaterial to fabricate a duct blank, combining a strengthening sheetingalong one side thereof, along which cuts corner joints may besubsequently structured said method using a reelable type linearmeasurer which has its housing attached to a base arranged fordemountable carriage atop the blade portion of a T-square comprisingsaid guide-edge, and with its zero end attached to a distance gaugecomprising diagramatically indexed alignment means along its sides,resulting in a procedure which automatically makes compensatingallowances for the material lost in the cutting process, to set theguide -edge positions in terms numerically the same as said specifiedinside dimensions, comprising the steps of;placing the insulating boardmaterial on a cutting table or support with its sheeting side down,removing a portion of the board along a beginning edge thereof to form arabbet, mounting the linear measurer atop the blade portion of theT-square which has its head portion against a side of the cutting tableparalleling the direction of measurement, selecting from diagrammeddata, on the side of the gauge, an alignment means which is to be usedwhen measuring from a rabbeted edge to set the guide-edge for a groovecut, placing this alignment means in alignment with the rabbeted edge,which offsets the linear measurer, in the direction of the measurement,a distance equal to the width of the rabbet plus one half of the widthof the groove, plus that width of the groove-cutting tool lying betweenthe center of the groove and the edge of the tool adjacent theguide-edge, moving the T-square in the direction of measurement untilthe linear measurer, as it unwinds from its housing, indicates, at itsintersection with the guide-edge of the T-square, the required insidedimension of the side of the structure being layed-off, holding theT-square in this position, removing the gauge and measurer frominterference, and moving the groove cutting tool along said guide-edgeto cut a first groove which will allow a first corner to be subsequentlyformed therealong and will define a first side of the structure lyingbetween the intersection of the inside surfaces along said corner, andthe near edge of the aforesaid rabbet cut, of the required insidedimension, again placing the measurer atop the blade portion of theT-square, selecting the alignment means which sets the position of theguide-edge for a cut when measuring from a groove to a groove, andplacing the alignment means in alignment with the groove cut just cut,moving the T-square in the direction of measurement until the requiredinside dimension after fabrication of the side being layed-off, asindicated by the linear measurer, intersects the guide-edge; holding theguide-edge in this position, removing the measurer from interferencewith the cutting process, moving the groove cutting tool along the edgeto cut a second groove; repeating the sequence of procedures outlinedabove for cutting the second groove to cut a third groove; again placingthe linear measurer atop the blade of the T-square, selecting, from thediagrammatical data on the sides of the gauge, the alignment means whichoff-sets the measurer the compensating distance necessary when measuringfrom a groove to a cut for a butt edge, placing this selected means inalignment with the immediately prior groove cut, moving the T-square inthe direction of measurement until the measurer, unwinding from itshousing, indicates, at its intersection with the guide-edge, therequired inside dimension of this, the fourth side of the structure,holding the guide-edge in this position, removing the measurer frominterference, making a knife cut, along said edge, vertically throughthe board material down to, but not cutting, the sheeting, to form abutt edge; again placing the measurer atop the blade of the T-square,selecting the alignment means along the side of the gauge for use whenmeasuring from the butt edge to define a stapling flap, placing thisalignment means in alignment with the knife cut just made, moving theT-square in the direction of measurement until, as there is no insidedimension involved, the zero inch mark of the measurer intersectss theguide-edge, holding the guide-edge in this position, making a verticalknife cut through both the insulating material and the sheeting, thenmaking a horizontal knife cut along the edge, thus exposed, between theinsulating portion and the sheeting, separating the two to leave astapling flap; and, then bringing the butt edge up and over to mate withthe rabbet of the first edge to close the four sides of the structure.